1. Field of the Invention
The present invention relates to a chemical supply system and a chemical mixing apparatus for use in manufacturing a semiconductor device.
2. Description of Related Art
A variety of different kinds of chemicals, including gaseous chemicals, liquid chemicals and gel chemicals, are used in manufacturing semiconductor devices. During semiconductor manufacture, these chemicals are usually supplied or delivered in the form of a chemical mixture comprising two or more kinds of chemicals that are mixed. Accordingly, efficient mixing and proper filtering of the chemical mixture are important factors in ensuring high quality delivery of the various kinds of chemicals to semiconductor manufacturing processes.
Recently, as the level of integration or density in semiconductor devices has increased, the design rule has become increasingly fine. It is difficult, however, to satisfy such fine design rules using chemicals having a low selecting ratio. Accordingly, chemicals having a high selection ratio have been developed in order to meet the demands and requirements of fine design rules. Such chemicals having a high selection ratio are generally made by mixing two or more different chemicals.
Chemicals having a high selection ratio, however, are prone to exhibiting problems during application in a manufacturing process. For example, defects occur on a surface of a semiconductor wafer during a manufacturing process due to chemicals having a high selection ratio. One of the causes of such defects is due to the generation of large-sized particles when the chemicals become exposed to external air before mixing. Another cause is due to chemical particle growth at dead points in the delivery channel, such as may exist in a tube at joint portions or bending portions.
When a chemical mixture containing such large-sized particles is supplied and used in a deposition process during semiconductor manufacture, there is a high probability that the chemical mixture will not be properly deposited on a semiconductor wafer with a tendency of the chemical mixture to form an overhang. In the case of an etching process, an over-etching occurs at a portion on which large-sized particles are positioned. In the case of a chemical mechanical polishing (CMP) process, fine scratches occur due to the large-sized particles.